Transcript Bone Growth and Development

 List
types of bone
 Know the function of cells involved in
bone growth
 Describe the two methods of bone
formation in detail
 Explain the factors that affect bone
growth
 Bone
Resorption
 Osteo
– greek for bone
 Osteogenesis – formation of bone
 Occurs both prenatally and postnatally
 Chondro-
cartilage
 Two
methods of bone formation
• Endochondral Ossification
• Intramembranous Ossification
 Endochondral
Ossification
• Ossification from a cartilage template
 Intramembranous
Ossification
 Ossification in the absence of a cartilage template
 Compact
bone – hard layer around the
outside
 Spongy
bone
• Trabeculae
• Spicules
 Medullary
bone
 Metabolically
 Used
active layer found in birds
as an available source of calcium
for egg shell production
 Osteoblasts
– involved in the bone matrix
production
 Osteocytes
– mature osteoblasts;
Responsible for maintenance of the bone
matrix
 Chondroblasts/
Chondrocytes – Form
cartilage that is associated with bone and
can be required for bone growth
• Long bones require cartilage before bone can
be made
 Osteoclasts
– involved in bone
reabsorption (breakdown) and
remodeling.
 Osteoblast/Osteocytes
 Bone
lining cells – inactive cells found on
the surface of bone that may serve as
osteoblast precursors.
 Fibroblasts
– part of connective tissue
proper that is associated with
synthesizing fibers and ground
substance.
• Ligaments and tendons
 Ossification
that occurs with the
replacement of cartilage with bone
 Prenatally
a cartilaginous structure
develops that will serve as the template
for ossification
 Ossification
of cartilage around the
outside of the diaphysis
 Primary ossification center in the central
portion of the diaphysis
 Secondary ossification center is
established in the center of each
epiphysis
A
thin layer of articular cartilage remains
on the surface of each epiphysis to
reduce friction
 Growth
plate
• Increases the length of long bones
 Growth
of cartilage on the epiphyseal
side
 Ossification of cartilage on the
diaphyseal
 The
growth of long bones will continue as
long as the rate of cartilage growth
remains faster than the rate of osteoblast
invasion into the growth plate
• It groaws until the growth plate ossifies
 Epiphyseal
closure – fusion of the
diaphysis and the epiphyses into a single
bone
 Example
is the break joint in lambs
under 12 months of age
 Bone
formation that occurs with the
replacement of connective tissue with
bone, but in the absence of cartilage
 Occurs in the formation of bones of the
skull
 Responsible for increasing bone
diameter
 During
bone growth, osteoclasts are
removing bone from the inner surface
and enlarging the marrow cavity
 Balance
between growth on the exterior
and degredation on the interior
 Red
marrow
• Chief site of red blood cell formation
 Yellow
marrow
• Composed mainly of adipose tissue and is found
in the medullary cavity of bones
 Is
a balance between osteoblast
formation and osteoclast degredation
 Bone remodling allows bones to adapt to
stresses
 Heavily stressed bones becomes thicker
and stronger
• Increased muscle growth will result in increased
bone growth at the protuberances of bone
 Remodling
is usually initiated through
osteoclast activation and removal of the
bone matrix
 Followed by osteoblast production of new
bone
 Vitamin
and mineral deficiencies can
result in abnormal bone growth
 Management strategies uncouple the
balance of muscle, bone, and fat growth
so that an immature skeleton must bear
excess muscle and fat mass
 List
types of bone
 Know the function of cells involved in
bone growth
 Describe the two methods of bone
formation in detail
 Explain the factors that affect bone
growth